In 2017, a group of scientists sent messages to any advanced alien civilization living in a star system 12.4 light years away, hoping to receive a response in 25 years.

Wolves are legendary because of their spine-tingling howl, which they use to communicate. A lone wolf howls to attract the attention of his pack, while communal howls may send territorial messages from one pack to another. Some howls are confrontational. Calls may be answered by rival packs. Much like barking domestic dogs, wolves may simply begin howling because a nearby wolf has already begun.